This invention relates to a dentifrice having reduced abrasivity and increased cleaning and stain removal properties comprising a linear water-soluble, polymer having a high molecular weight of over 1,000,000 selected from the group consisting of polyacrylamide derivatives such as partially hydrolyzed polyacrylamide, and guar gum double derivatives such as hydroxypropylated carboxymethylated guar gum, and an abrasive system of dentally acceptable polishing agents, typically selected from the group consisting of a siliceous polishing agent, a calcined alumina and mixtures thereof.
It has been difficult heretofore to provide dentifrices for use in the daily brushing and cleaning of teeth which provides a desirable balance of cleaning and abrasive action. This has been largely due to the difficulty in selecting suitable abrasives which will afford maximum removal of difficult stains and debris without damaging the oral hard tissues (enamel, dentin and cementum), particularly the dentin surfaces.
The prior art has addressed the problem of decreasing the abrasivity of dentrifices as disclosed in U.S. Pat. No. 4,102,992 wherein water-insoluble organic polymers such as the thermoplastic acrylics (polymethyl methacrylate and polyisobutyl methacrylate), cellulosics, polyamides, polyethylene, polystyrene and the vinyls, which are less abrasive than the calcium carbonate polishing agent, are added to the dentrifice composition.
U.S. Pat. No. 4,144,322 discloses the reduction of enamel abrasiveness in dentifrices comprising a dental abrasive system of hydrated siliceous abrasive and the hard abrasive calcined alumina, and about 1-5% by weight of a calcium, magnesium or sodium salt which effects a reduction in the radioactive enamel abrasion (REA) of the dentifrice.
U.S. Pat. No. 4,407,788 and British Pat. No. 2,100,983B disclose a siliceous polishing material and a small amount of a water soluble resinous poly(ethylene oxide) and maltitol humectant which improves stain removal without raising radioactive dentin abrasion (RDA).
However, there is no disclosure of the use of the high molecular weight, linear, water soluble polymers, particularly partially hydrolyzed polyacrylamides and the hydroxypropylated carboxymethylated guar gum to reduce dentin abrasivity of a dentifrice composition containing an abrasion system having maximum cleaning and stain removal properties without causing undue abrasion to the oral hard tissues, particularly the dentin layer.
The prior art also discloses guar gum as a thickening agent per se, or in combination with other components, such as abrasives in dentifrice compositions as shown in U.S. Pat. No. 3,723,408 wherein is disclosed the process for preparing the hydroxyalkyl ether derivative of polygalactomannan (guar gum), but does not disclose the use of guar gum derivative and particularly, not for a double substituted guar gum derivative in a dentifrice to reduce dentin abrasivity.
U.S. Pat. No. 4,122,162 discloses oral compositions for inhibiting plaque, containing as the gelling agent, a cellulose ether, guar gum or colloidal silica, and conventional abrasives such as the calcium phosphates, alkali metal metaphosphates, silicon dioxide, hydrated alumina oxides and aluminum silicates. However, there is no disclosure of the hydroxypropylated carboxymethylated guar gum. There is no mention of abrasivity or stain removal.
U.S. Pat. No. 4,081,526 also discloses an antiplaque composition containing suitable gelling agents including guar gum and conventional polishing agents such as calcium phosphate dibasic dihydrate, calcium carbonate, calcium pyrosphosphate, aluminum hydroxide, silica, kaolin or alumina. There is no mention of abrasivity or stain removal.
U.S. Pat. No. 4,374,823 discloses a dental composition having proper viscosity flow rate and ribbon shape retention containing a gelling agent mixture of xanthan and guar gum, a sorbitol humectant and a suitable water insoluble polishing agent.
However, there is no disclosure in the prior art of dentifrice compositions containing linear, water soluble, high molecular weight polymers selected from the gro consisting of polyacrylamide, partially hydrolyzed polyacrylamide and hydroxypropylated carboxymethylated guar gum, and any suitable dental polishing agent, typically a siliceous abrasive and/or a hard abrasive such as calcined alumina, having reduced dentin abrasivity and increased cleaning and stain removal properties.